Broaching machine



Feb. 7, 1939. A. L. NlLssoN BROACHING MACHINE Filed Jan. 30, 195;?vZSheetS-Sheet l A, L. NlLssoN Feb. 7, 1939.

BROACHING MACHINE 2 Sheets-Sheet 2 Filed Jan. 30, 1937 Patented Feb. 7,1939 Nrreo g STATES PATENT OFFICE Application 'January rr30, 1937,Serial'No. 123,169

i12 `Claims.

The .present invention .relates to breaching machines, and in particularproi'li'des 4an improved breaching machine for forming .one `ormorehelical serrations onthe surfaceof a work piece.

'.It has 'heretofore `been proposed to utilize broaches'and breaching.machines to.`form helical serrations .on the .outer periphery of a workpiece t`o`form,'for example, .external yhlicalgears or 'gear' segments.Conventionally, r a closedlbroach bodyfis utilized, having .innerhtelically disposed teethjaround allor a portion of the-innenperipherythereof, dependingupon whether .the serrations or'teeth .are ,to extend`entirely around the periphery of the work piece vor aroundonlyapredetermined segment or portion -thereof. Alternatively, and inaccordance with .the .improvements .proposed .in 4the y(so-pending`application ofWilliam L'Hart, ySerial No. 111 ,'0'00, .nled Novemberl16., .1936 and rassigned to the ,assignee of the present application,the 'broachis formed asa -.plurality .of segments, each-of .which.segments is effectiveto rform the serrations or teeth in @predeterminedportion ofthe periphery of the Work piece. Therespective segments .arepreferably v.disposed in axially disposed relation, in order toafford'free access to theY interior rof the broach .for chip clearanceand thelike. The axial movement of the Work piece relative 'to thebroach is accompanied by a relative rotation between the members, "thedegree oi which corre- .spondsto the vdesired helix angle of theserrations or teeth. n AAs will'be appreciated, theheretofore proposedmethod of broaching helical serrations on the `external periphery 4of awork piece are .practical only in connection with Work pieces which canbepassedaxially through the rbroa'ch'body; that is, work pieces havingan external periphery which adaptsrthem to be bodily passed throughthe'ibroach. This limitation .has prevente'dfthe extension oi broa'chingto the .manufacture of devicessuch .as a crank arm .havingahelical gearV.segment .formed .at ,one ,end thereof .f

..In accordance with the `presentinventiomthe justmentioned limitation.is ventirely overcome, and the field for broaching .correspondinglyWidened,`by`forming .thelbroach body'in the form f an open helix, theangle of which corresponds to the desired yhelixrangle of the broachteeth.

and'positioning the broach teeth on the inner surface `of "this -openhelix, With this 'arrangement, *thesopen helix vof the vbroachvaccommodates-the 'projecting fpart vof the'work piece, 'such astthearmof the just mentioned'crank, "and permits the .toothed .portion of thework vpiece to be serrated or provided with vhelical teeth yto bereadily presented tothe broach teeth. .The broaching operation may thusconsist in moving the work .piece axially of the .broach and inrelatively rotating the Work piece and `broach about the axis ofthebroach. .Claims to theimproved'broach are presented in applicants copending application, Serial No.l 123,168, filed January 30, 1937, and.assigned to the same assignee asthepresent application, and the presentapplication is directed particularly to the improved breaching machine.

With the foregoing considerations in mind, objects of the presentinvention are to provide an improved machine for .breaching externalhelical gear elements, .utilizing a .broaching ,tool formed as an open.helix and .having helically disposed vbreaching `teeth .on theinnersurface thereof ,.and utilizing means to eect axial linear movementand `angular rotation of the broach relative to a workpiece; to providesuch a machine utilizing abroach draw head for eiiecting 'theaxiallinear movement of thev broach relativev to the Work piece, andutilizing a master lead screw 4for effecting 'the axial rotation of thebroach relative lto the Work piece, the lead screw being adapted totelescopically enter the'broach body; .toprovide such a machinevutilizingrelatively .stationary Work supporting .mechanism adapted .tosupport .the workso that it .projects into thefbroach through the openhelix of the latter to present the surface to be broached to thebroachteeth; to provide such a machine in which-a plurality of work pieces tobe provided With `one or more helically disposed serrations, may besupported in superposed and angularly offset relation; yand to providesuch a machine utilizing a plurality of breaches, certain of which areadapted vto 4form left-handed helical serrations .in nWork pieces andothers .of which are adapted to form right-handed serrations in Workpieces.

-,Other genericas Well as umore detailedv objects ofthepresent inventionVappear in the following descriptionand inthe lappended-claims. In thedrawings, which illustrate a preferred .but illustrative embodiment ofrthe invention, and throughout which corresponding reference charactersare used'to designate corresponding parts:

vFigure '1, is aperspective vieW in front elevati'on "of a 'machineembodying the present, invention;

l Fig.2 is a iragm'entaryview'with certain of the 'partsbroken away,showing the relation of the improved broach and work supportingmechanism of the machine of Fig. 1;

Fig. 3 is a top plan view showing additional details of the work holdingmechanism of the machine of Fig. 1,'

Fig. 4 is a fragmentary detailed view showing details of the broachstructure; and

Fig. 5 is a perspective view of an illustrative work piece which may bebroached in the practice of the invention.

Referring to the drawings, the machine is illustrated as of the verticalpush type, designed to accommodate two helically formed broaches 26,which are adapted to be moved downwardly as viewed in Figs. l and 2under the influence of a cross-head 22, which is actuated by the piston(not shown) of suitable hydraulic ram mechanism 24. The cross-head 22 issuitablyA guided by columns 23. The broaches 26 are shown in their upperpositions, and a downwardmovement thereof as effected by the rammechanism 24 causes them tc move past the stationary work table 26 whichprojects Yfrom the front of the frame 28 of the machine.

As described in detail in applicants above identitled co-pendingapplication, Serial No. 123,168, each of the broaches 26 is formed as anopen helix, of a lead corresponding to the lead of the helicalserrations of the teeth which it is desired to produce upon the workpieces and having correspondingly helixed broach teeth disposed on theinner surface thereof. The teeth 26a of each broach 2D, which increasein height from the lower end of the broach as viewed in Fig. 2 to theupper endthereof, are disposed on a helix angle corresponding to thehelix angle to be produced in the work piece, and to which helix anglethe general open helix of the broach as a whole, of course, corresponds.i

VThe upper end of each broach 20 is formed as a trunnion 36 which isrotatably journaled between ball thrust bearings 32 with a broach head34. The shank 36 of each head 34 may be connected to the previouslymentioned cross-head 22 in any suitable way, so that downward movementof the cross-head22 causes a corresponding downward movement of eachbroach 20, while: at the same time permitting axial rotation of thebroach 26.

Each broach 26 is guided within a cylindrical sleeve 40, suitablysup-ported within the main frame portion 42 and the lower end of thebroach is provided with a counter-bore 44, which rotatably receives ahead 46 which is secured to the upper end of a master lead screw 48. Thelower end of the lead screw 48 is keyed as by a key 50 to a collar 52,suitably secured to the underside of the just mentioned frame portion42. The lead screw 48 is provided with a single or multiple helicalgroove 54 and a driving collar 56 is provided with similarly formedhelical tongues which enter the grooves 54, in order to provide arotative driving connection between the broach 20 and the lead screw 46.The collar Y56 is secured to the lower end of the broach 2U by one ormore studs 58.Y With this arrangement, as will be appreciated, adownward movement of the broach 20 causes the driving collar 56 torotate about the lead screw 48, as determined by the lead ofthe screws54, and this rotation causes a corresponding axial rotation of thebroach 20. It will be appreciated that the leads of the broach teeth 26aand of the screw 48 correspond to each other. VReferring particularly toFig. 5, it will be appreciated that the improved broaching machineopposite leads.

ofv the present invention may be practicedV in broaching helicalserrations or teeth in work pieces of a wide variety of forms,characterized generally as having a shape or size which prevents theirbeing passed through a body of a conventional enclosed circular or ringbroach. The work piece 65 shown specifically in Fig. 5 as Well asgenerally in the other gures, represents a portion of mechanism of avehicle, and includes a shank or crank portion Staand a segmental toothportion having helically disposed teeth 60h having a bearing opening 60oconcentric therewith.

As shown in Figs. 2 and 3, in order to permit a plurality of work piecesto be broached during the window regulating each pass of each broach 20,they are disposed upon the work table 26 inV superposed but angularlyoffset relation, with the faces Vthereof in overhanging relation to thetable 26. A pin 62 projects upwardly from the work table 26 at the axialcenter of the associated broach, and also projects through the bores 66eof the work pieces 60. The work pieces 60 are retained in assembledrelation to the pin 62 by a clamping bar 64, having a bifurcated end 66,and pivotally supported within a clevis 68 upon the work table 26. Aconventional screw mechanism 16 may be provided to rock each clamp 64about its pivot pin 12, in order to force the bifurcated end 66 thereofdown upon the work pieces and clamp them in place. In addition to thejust described clamp 64, the work table 26 preferably additionallyaccommodates a plurality of clips 14equal in number to the number ofwork pieces 60, each of which is provided at its forward end withupstanding leg portions 16, which receive the extreme end of theassociated work piece. f

As clearly appears in Fig. 1, and as indicated by the arrows in Fig. `3,the two broaches 20 are oppositely disposed and are adapted to berotated in respectively opposite directions, one thereof being adaptedto cut left-handed threads in the Y associated work pieces 60 and theother thereof being adapted to cut right-handed threads in theassociated work pieces. The reverse directionof rotation of the broachesmay be effected, as will be appreciated, l,by providing the lead screws48 individual thereto with slots 54 of respectively The work holdingmechanisms for the twobroaches 20 may be duplicates of each otherasclearly appears in Fig.v 3, except thatk the workpieces 66 broaches. Yf Considering the operation of theV machine as a are oppositelypresentedto the whole, it will vbe appreciated that the two broaches i20 normally occupy the illustrated upper positions thereof and that as apreliminary to a broaching operation, a plurality of work pieces 60 tobe broached withthreads of one hand are stacked upon the pins 62associated with oneV Vof the broaches and that a correspondinglyplurality of work pieces to be provided with threads of opposite handmay be stacked upon the pins 62 associated with the other broach. Theguide elements 'I4 facilitate the positioning ofY the work pieces inrproper angularly offset relation to each other and the Ysetting upoperation is completed by clamping each of the clamps 64Y over theassociated pin 62 and down upon the associated work the broaches 20 arerotated and, in a single pass 15 thereof are effective te. completelycut the'helical teeth 6.011; in all ofthe Werk pieces.V

Although a specic embodiment of theinventiem-,has beenshown in detail,it. will be appreoiated thatA various modifications in the form,numbenand arrangements of'parts, may be made within the spirit and scopethereof.

s WhatI claim is:

1,. In a machine for breaching one ormoreghelicallydisposedserrations-.en the exterior of a work piece,thecoinbinati'enefa breach of open generallylheligcal, formation, thesuccessive turns where.- ef: are spaced apart from each other so. as. tepermitthework piece to be laterally admitted to theyl interior of the.breach, said breach having helically; disposed breach teeth on the.inner surfaea thereof, meansv for supporting said work piece-sethat itvextends. laterally into the breach withcsaidaexterior presented te said.breach teeth,

and means for eecting linear'reciprooation and IOtatinefsaidbroach and'said werk piece relative to each other.

2. In a breaching machine for forming one or more helically disposedserrations on an external surface of a werk piece, the combination of abreach of open generally helical form, the successive turns whereof arespaced apart from each other so as to permit the Work piece to belaterally admitted te the interior of the breach, said breach havingbreach teeth formed on the inner surface thereof, means for causinglinear movement of said breach, means for supporting a work piece sothat it extends laterally into the breach with said surface thereofpresented to said breach teeth, and means for effecting relativerotation between said work piece and said breach about the axis of saidbreach during said linear movement of said breach.

3. In a breaching machine for forming one or more helical serrations onan external surface of a work piece, the combination of a breach of opengenerally helical formation, the successive turns whereof are spacedapart from each other so as to permit the work piece te be laterallyadmitted to the interior of the breach, said breach having helicallydisposed breach teeth en the interior l surface thereof, means foreffecting linear axial ras movement of said breach and for effectingaxial rotation thereof in timed relation to said axial movement, andmeans for stationarily supporting a work piece se that it extendslaterally into the breach with said external surface thereof presentedte said breach teeth.

4. In a breaching machine for forming one er more helically disposedserrations on the external surface of a werk piece, the combination of abreach of open generally helical formation, the` successive turnswhereof are spaced apart from each other se as to permit the work pieceto be laterally admitted to the interior of the breach, said breachhaving helically disposed breach teeth on the interior surface thereof,means for effecting linear axial movement of said breach, a lead screwdrivingly connected to said breach and adapted to be telescopicallyreceived therein during said linear movement for effecting axialrotative movement of said breach duringsaid linear movement, and meansfor statienarily supporting a work piece so that it extends laterallyinto the breach with said external surface thereof presented to saidbreach teeth.

5. In a breaching machine for forming one er more helically disposedserrations on the external surface of a work piece, the combination of abreach of open generally helical form, the successive turns whereofarevspaced apart from each other se.v as to permit the work piece to belaterally admitted to the interierof the breach, said breachhavingbroach teethl onthe inner surface thereof, av work table, meansfor effecting rotative and linearly axial movement between said breachand saidwork table, and a Work helder for supporting a; pluralityefworkpieces in superimposed angularly offset relation soythat theyextend laterally into the breach withsaid external surfaces thereofpresented to said breach.

- 6. In a breaching machine for forming one or morehelicallydispesedserrations en the external surface. of a work piece, the combination ofa breachef .open generally helical form, the successive turns. whereofare spaced apart from each other so as to permit the werk piece to belaterally admitted. to the interior of the breach, said breach having.breach teeth on the inner surface thereof awork table, means foreffecting rotative andglinearly axial movement between said breach andsaid werk table, and means for supporting said work piece with saidprojecting portion thereof passing through the open portion of saidbreach and with said external surface thereof presented to said breachteeth.

'7. In a breaching machine for forming one or more helically disposedserrations on the external surface of a work piece having a projectingpart, the combination of a breach of open generally helical form, thesuccessive turns whereof are spaced apart from each other se as topermit the work piece to be laterally admitted to the interior of thebreach, said breach having breach teeth en the inner surface thereof, awork table, means for effecting rotative and linearly axial movementbetween said breach and said work table, and means for supporting aplurality of said werk pieces with said external surfaces: thereof insuperposed angularly offset cutting relation to said breach teeth, andwith the projecting pertions thereof projecting outwardly of said breachthrough the opening in the body thereof.

8. In a breaching machine for forming one or more helically disposedserrations on the external surface of a work piece having a projectingpart, the combination of a breach of open generally helical form, thesuccessive turns whereof are spaced apart from each other so as topermit the work piece to be laterally admitted to the interior of thebreach, said breach having breach teeth on the inner surface thereof, awork table, means for effecting rotative and linearly axial movementbetween said breach and said Werk table, and a werk holder for said workpiece including said werk table, a guide pin projecting from said Werktable disposed to pass through a bore in said work piece to axiallycenter the same, a clamp disposed to bear upon said Work piece, and aguide element for the projecting portion of said work piece.

9. In a machine for breaching one or more helically disposed serrationson a werk-piece, the combination of a breach having a body of striplikeform wound in open generally helical fermaa tion with the successiveturns spaced apart axially and having a plurality of cutting teethformed thereon, means for supporting said work-piece se as to projectlaterally towards said breach body with the breach teeth presented tothewerk-piece surface, and means for effecting linear reciprocation androtation of said breach and said workpiece relative to each other.

l0. In a machine for breaching one er more helically ldisposedserrations en a work-piece, the

combination of a breach having a body of striplike form wound in opengenerally helical formav tion With the successive turns spaced apartaxially and having a plurality of cutting teeth formed thereon, meansfor causing linear movement of said broach, means for supporting a.work-piece so that it extends laterally towardthe broach with saidsurface thereof presented to said broach teeth, and means for eiectingrelative rotation IbetweenV said Work-piece and said broach about theaxis of said broach during said linear movement of said broach. y

11. In a machine for broaching one or more helically disposed serrationson a Work-piece, the combination of a bro-ach having a body of striplikeform wound in open generally helical formation with the successive turnsspaced apart axially and having a plurality of cutting teeth formedthereon, means for effecting linear axial movement of said broach andfor eiecting axial rotation thereof in timed relation to said axialmovement, and means for stationarily supporting a tion with thesuccessive turns spaced apart Yaxially Y and having a plurality ofcutting teeth formed thereon, means for supporting said work-piece so asto project laterally towards said broach body with the broach teethpresented to the Work-piece Y surface, means for effecting linearreciprocation and rotation of said broach and said Work-piece relativeto each other, and means for effecting relativerrotation .between saidbroach and said Work-piece during said linear movement including a leadscrew drivingly connected to said broach and disposed to betelescopically received into the body of said broach. Y Y A AXEL L.NILSSON.

